1. Field of the Invention
The present invention generally relates to torsion axles and suspensions as used in vehicles such as trailers and, more particularly, to a configuration of torsion system as used in torsion axles and torsion suspensions.
2. Background Art
Torsion axles represent a cost-effective way to provide some independent suspension to the wheels of vehicles. Because they are cost-effective, torsion axles and torsion suspensions are commonly used with low-priced vehicles, such as hitched trailers.
Referring to FIG. 1, a torsion axle in accordance with the prior art is generally shown at 10. The torsion axle 10 has a hub 11 upon which a wheel (not shown) is mounted. The hub 11 is supported by a free end of a crank arm 12. The other end of the crank arm 12 is connected to a torsion system that has a housing 13 of rectangular section, a shaft 14 in the housing 13, and elastomeric members 15 compressed within the housing 13. The shaft 14 has a selected section so as to exert pressure against the elastomeric members 15 when rotating within the housing 13. It is therefore the elastomeric members 15 that provide the shock absorption.
Referring to FIG. 2, a torsion suspension of the prior art is generally shown at 16, and is generally similar to the torsion axle 10, whereby like elements bear like reference numerals. The torsion suspension 16 has a pair of crank arms 12, and the output ends 17 can be used as hubs. The crank arms 12 are optionally independent from one another, in which case each crank arm 12 has its own shaft within the housing 13.
The torsion axles and suspensions of the prior art are currently manufactured by insertion of elongated members 15 of elastomeric material between the shaft 14 and the interior of the housing 13 (FIG. 1). As non-negligible pressures are involved in fitting the shaft 14 and the elongated members 15 in the housing 13 under compression, equipment such as hydraulic presses and freezers is required, therefore resulting in an increase in price of the torsion axle/suspension. Under these circumstances, it is difficult to repair a torsion system if the elastomeric material is damaged or worn. Also, torsion axles/suspensions often have to be delivered from the manufacturer completely assembled.